Without limiting the scope of the present invention, its background will be described with reference to transporting semiconductor wafers from one site to another.
Heretofore in this field, it has been necessary to transport semiconductor wafers from one fabricating facility to another between certain steps in the fabrication process. The process for packaging the semiconductor wafers for shipment was typically a manual process which required placing each of the semiconductor wafers into individual electrostatic discharge bags in order to prevent the buildup of static charge on the semiconductor wafer that may otherwise occur during handling. The static charge must be prevented in order to avoid causing short circuits within the semiconductor wafer.
Once the semiconductor wafers were placed into electrostatic discharge bags, the semiconductor wafers were placed into a styrofoam box. The styrofoam box was typically treated with a topical anti-static coating such as Staticide made by ACL Corporation or other quaternary compounds. The use of the topical anti-static coating on the styrofoam box further prevented the buildup of static charge during handling of the semiconductor wafers.
It has been found, however, that the use of styrofoam boxes could promote the corrosion of semiconductor wafers due to the potential moisture retention by the styrofoam. The typical process used to mold the styrofoam box is a steam process wherein beads of styrofoam are exposed to steam which causes them to expand and allows them to be formed into the shape of a box. If the styrofoam boxes are not properly dried, the residual moisture within the styrofoam box may cause corrosion of the semiconductor wafers.
The use of styrofoam boxes also left semiconductor wafers susceptible to breakage. For example, it is estimated that between one and three percent of semiconductor wafers were broken during the manual loading and unloading process as well as during transportation of the semiconductor wafers in the styrofoam box. In addition, the use of styrofoam boxes to transport silicon wafers resulted in high costs associated with the manufacture and disposal of the styrofoam boxes which in most cases were not re-used or recycled.
Therefore, a need has arisen for a containment device for retaining semiconductor wafers that will allow for automated loading and unloading of semiconductor wafers, thereby minimizing the breakage of semiconductor wafers associated with the transportation of semiconductor wafers from one facility to another. A need has also arisen for such a containment device that dissipates static charge without the need to manually place the semiconductor wafers within an electrostatic discharge bag. A need has further arisen for a containment device for retaining semiconductor wafers that does not promote corrosion of the semiconductor wafers. Additionally, a need has arisen for such a containment device that is re-usable, thereby minimizing both the manufacturing and disposal costs associated with transporting semiconductor wafers.